Device for combine harvesters equipped with a rotary straw chopper

ABSTRACT

A device for combine harvesters (11) equipped with impact straw cutters (16) of the kind equipped with a cleaning device (13) for separation of chaff from the grain and which rotary chopper is connected to the straw outlet (17) of the combine harvester, whereby the chaff coming from the cleaning device (13) and being transported by a flow of air is intended to be supplied to the rotary chopper (16). The rotary chopper is connected to the straw outlet (17) of the combine harvester. The purpose of the invention is to provide a device by which the chaff is spread over the entire harvesting breadth of the combine harvester and is also efficiently admixed with the comminuted straw such that a continuous and even distribution can be obtained on the field. This has been solved by designing the rotary chopper (16) as a lateral flow blower which is arranged to create a negative pressure at the inlet (21) of the rotary chopper, and the outlet of the cleaning device (13) is directed obliquely upwards towards the fall-out area of the straw above the inlet (21) of the rotary chopper such that the chaff is mixed with the straw prior to their reaching the rotary chopper and that the flow of air transporting the chaff to the inlet of the rotary chopper is so dimensioned as to have a pressure within the fall-out area of the straw which slightly exceeds the atmospheric pressure.

The present invention refers to a device for combine harvesters equippedwith rotary straw chopper, of the type equipped with a cleaning devicefor separated the chaff from the grains. The rotary chopper is connectedto the straw outlet of the combine harvester, whereby the chaff comingfrom the cleaning device and transported by a flow of air is intended tobe supplied to the rotary chopper.

BACKGROUND OF THE INVENTION

Combine harvesters generally have a pickup reel with a cutting table,which can be twice as wide as the width of the harvester. This meansthat during harvest of straw fodder plants, the chaff after the treshingwill be deposited on the field in a rather narrow string, which mainlycorresponds to the width of the cleaning device. It nowadays is usualthat the straw after treshing is cut and spread over an area mainlycorresponding to the width of the cutting table, in order to allow it tobe plowed into the soil. The field therefore will have row-formed areas,where the content of disintegrated straw and chaff is bigger than inadjacent areas, which almost entirely lack an admixture of chaff. Thisuneven distribution results in different growth conditions due to thefact that the growth is hampered in the areas where the soil containstoo much disintegrated, but non-mouldered straw and chaff.

There are known treshing machines for treshing cut straw fodder plants,where the chaff from the cleaning device is supplied to a rotary chopperor a straw shredder. The purpose of this mixing of straw and chaff is toimprove the nutritional value, in the case where straw is used asfodder. For this reason the rotary chopper outlet is usually equippedwith a pressing device, which crushes the straw and the ears.

It was proven that the known technique is impossible to use, as themodern rotary chopper creates a positive pressure about the rotor, whichpressure is so big so that the chaff is blown away, causing a blockingof the straw inlet. It also has been tried to feed the chafftangentially in through a separate opening in the rotary chopper or thestraw shredder, but the same problem also occurs in this case, i.e. thepositive pressure from the rotor prevents the chaff from entering therotary chopper. According to another suggestion (British patent No. 4220from 1893) the chaff is transported by means of a particular blower viaa conduit system to a position above the inlet of the rotary chopper. Inorder to transport the quantities of chaff concerned a rather bigpositive pressure in the blower is required, which means that an aircushion is created above the rotary chopper, which may cause the strawfeed to be blocked.

THE PURPOSE AND MOST IMPORTANT FEATURES OF THE INVENTION

The purpose of the invention is to provide a device by which the chaffis spread over the full harvesting breadth of the combine harvester andis also efficiently admixed with the disintegrated straw, so that acontinuous and even distribution of material on the field can beobtained. The device thereby must be such that it does not affecttransportation of the non-chopped straw to the rotary straw chopper oradversely affect the separation of the grain from the chaff. Itfurthermore should be possible, if the rotary chopper is disengaged,e.g. if the straw shall be laid in rows, to deposit the chaff as earlierin a narrow row or alternatively to spread it over the full harvestingwidth of the combine harvester, without the straw thereby beingdisintegrated.

These tasks have been attained in that the rotary chopper is alsodesigned as a lateral flow blower, which is arranged to create, at theinlet of the rotary chopper, a negative pressure. Also, the outlet ofthe cleaning device is directed obliquely upwards towards the fall-outarea of the straw above the inlet of the rotary chopper. Thus, the chaffis mixed with the straw prior to reaching the rotary chopper and theflow of air transporting the chaff to the inlet of the rotary chopper isso dimensioned as to have a pressure within the fall-out area of thestraw which slightly exceeds atmospheric pressure.

DESCRIPTION OF THE DRAWINGS

The invention hereinafter will be further described with reference tosome embodiments.

FIG. 1 shows schematically the rearmost part of a combine harvester,partially in section, at the straw outlet of which is arranged a rotarychopper.

FIG. 2 is a view corresponding to FIG. 1, in which the transport deviceaccording to the invention is constituted by an auxiliary blower.

FIG. 3 shows likewise the rearmost portion of a combine harvester ofanother device type which is equipped with the transport deviceaccording to the invention and has the form of a belt conveyor.

DESCRIPTION OF EMBODIMENTS

In the drawings 11 designates the rearmost part of a combine harvester,12 is a rotational separator which forms part of the treshing machine ofthe combine harvester. 13 is a cleaning device, which consists of aplurality of sieves 14 and a cleaning blower 15. A rotary chopper 16 isconnected to the straw outlet 17 of a combine harvester. The strawchopper 16 is designed also to act as a transverse flow blower and is indue course equipped with a knife rotor 18, which cooperates withstationary counter knives 19, which are adjustable in differentinclinations in order to be adaptable to different types of goods to becut. The apparatus housing 20 of the rotary chopper is designed withonly two openings, one inlet opening 21 for the non-cut straw 22 and oneoutlet opening 23 to which is also connected a spreading device 24.

In conventional combine harvesters the chaff 25 is let out on the fieldthrough an opening directly after the sieves 14, which outlet opening issituated in front of the rotary chopper 16, and without communicatingtherewith. The chaff 25 is separated from the more heavy grains at thepassage through the sieves 14, whereby the more light material is blownaway in a direction towards the outlet opening 33 of the cleaning device13 by means of the air flow caused by the cleaning blower 15. Instead ofdischarging the chaff in front of the rotary chopper, the combineharvester according to the invention is so designed, that a transportdevice 26, e.g. in the form of a duct 27 establishes a passage betweenthe outlet 33 of the cleaning mechanism 13 and the inlet 21 of therotary chopper 16, such as shown in FIG. 1. The duct 27 therefore doesnot require a closed cross section but can be more or less open. As isevident from FIG. 1, there is a housing on the chopper 16 which includesa wall portion 20a which has a component which faces the duct 27 andwhich is sufficiently high that the inlet 21 into the chopper 16 isdefined above the chopper 16, i.e., above the radius of action (outerperiphery of chopper blades) thereof. The wall portion 20a extends fromthe inlet 21 to the outlet 33. Quite obviously, the chaff 25 and thestraw 22, therefore, enter the inlet 21 together.

If the conventional cleaning blower 15 of the combine harvester shouldhave a too small of an effect for transporting the chaff to the inlet 21of the rotary chopper or if the air pressure from the treshing machine12 should be so big that air is pressed "backwards" into the cleaningdevice, which could prevent the chaff from reaching the rotary chopper,it is suitable to provide an auxiliary blower 28, which is located suchthat the air flow caused by the blower creates a counter-pressure to theair pressure from the treshing machine, which air pressures are balancedso that the flows of material from the treshing machine and the cleaningapparatus will not obstruct each other. Such an embodiment is shown inFIG. 2, where the auxiliary blower 28 opens in the bottom of the casing29 of the cleaning device 13. The connecting sleeve coupling 30 of theauxiliary blower 28 is directed towards the passage 27, and therebysupports the flow of air created by the cleaning blower 15.

In some combine harvesters the treshed straw is transported from thetreshing machine via vibrating table 31 to the straw outlet 17 of thecombine harvester and if disintegration of the straw is desired thenthis it is transported to the rotary chopper 16. In these combineharvesters, shown in FIG. 3, the space between the cleaning device andthe rotary chopper 16 may be so big that the flow of air from thecleaning blower 15 is insufficient for transporting the chaff to theinlet opening 21 of the rotary chopper. For such combine harvesters thetransport device 26 is preferably designed as a belt conveyor 32 or thelike, which extends from the outlet opening 33 of the cleaning device 13to a position above the inlet opening 21 of the rotary chopper 16. Thewidth of the endless belt conveyor 32 corresponds to the width of theoutlet opening 33 of the cleaning device 13. In order not to disturb theflow of material on the belt conveyor 32 there is arranged a partition34 between the vibrating table 31 and the upper part of the beltconveyor 32.

The straw outlet 17 of the combine harvester is conventionally equippedwith horizontal guides 35, along which the rotary chopper may bedisplaced or be swung away if the straw shall be deposited in rows. Ithowever also is possible to open a shutter (not shown) above the rotarychopper and to let out the non-cut straw this way, whereas the cutter isused for spreading the chaff over the full working area of the combineharvester.

The invention is described in a number of embodiments and it is appliedin different modified connections. It is, of course, fully within thescope of the invention to combine structural details from one embodimentwith corresponding details from another embodiment, but also acombination of details from different varieties are possible. The beltconveyor thus can be used in the combine harvester shown in FIGS. 1 and2 and the passage and the auxiliary blower at the embodiment accordingto FIG. 3.

The invention is neither limited to the embodiments shown but aplurality of variants are possible within the scope of the claims.

I claim:
 1. A device for a combine harvester, for mixing straw and chaffand for spreading the same behind the combine harvester, the devicecomprising:a cleaning device for separating chaff from grain and a chaffdischarging means associated with said cleaning device for dischargingchaff; a rotary straw chopper having an axis of rotation which extendstransversely to a longitudinal dimension associated with said combineharvester; a housing extending about said rotary straw chopper, saidhousing defining an inlet into said rotary straw chopper and an outletfrom said rotary straw chopper, said outlet being circumferentiallyspaced from said inlet, said housing including a wall portion facingsaid chaff discharging means and extending from said inlet to saidoutlet, said wall portion extending upwards and reaching verticallyabove a radius of action of said rotary straw chopper, whereby saidinlet into said chopper is defined above said rotary straw chopper; andmeans for directing a flow of straw toward a fall-out region definedabove said inlet and wherein said chaff discharging means includes meansto cause the chaff to be discharged into said fall-out region to bemixed with the straw prior to reaching said inlet of said rotary strawchopper, said chaff discharging means being effective for creating aflow of air for transporting the chaff to the fall-out region at apressure that slightly exceeds atmospheric pressure.
 2. The device ofclaim 1, wherein said inlet extends transversely across said combineharvester.
 3. The device of claim 1, wherein said rotary straw chopperis constructed as a cross-flow blower whereby the same is effective tocreate a negative pressure at said inlet.
 4. The device of claim 3,wherein said chaff discharging means includes a wall which is disposedgenerally lower than said fall-out region and has a portion whichextends obliquely and upwardly so as to direct the chaff to be blowninto the fall-out region.
 5. The device of claim 4, the chaffdischarging means comprising a cleaning blower for blowing the chaff andduct means for guiding the flow of air from the cleaning blower so as toblow the chaff into the fall-out region.
 6. The device of claim 5,further comprising a chaff outlet at said cleaning device and anauxiliary blower disposed proximate to said chaff outlet for assistingthe discharging of the chaff.
 7. The device of claim 3, wherein saidchaff discharging means comprises a conveyer.
 8. The device of claim 7,wherein said conveyer comprises an endless belt conveyer.
 9. A devicefor a combine harvester, for mixing straw and chaff and for spreadingthe same behind the combine harvester, the device comprising:a cleaningdevice for separating chaff from grain and a chaff discharging meansassociated with said cleaning device for discharging chaff, said chaffdischarging means comprising a cleaning blower for blowing the chaff, achaff outlet through which the chaff discharges, and an auxiliary blowerdisposed at, or approximate to, said chaff outlet for assisting thedischarging of the chaff; a rotary straw chopper having an axis ofrotation which extends transversely to a longitudinal dimensionassociated with said combine harvester; a housing extending about saidrotary straw chopper, said housing defining an inlet into said rotarystraw chopper and an outlet from said rotary straw chopper, said outletbeing circumferentially spaced from said inlet, said housing including awall portion facing said chaff discharging means and extending from saidinlet to said outlet, said wall portion extending upwards and reachingvertically above a radius of action of said rotary straw chopper,whereby said inlet into said chopper is defined above said rotary strawchopper; and means for directing a flow of straw toward a fall-outregion defined above said inlet and wherein said chaff discharging meansincludes means to cause the chaff to be discharged into said fall-outregion to be mixed with the straw prior to reaching said inlet of saidrotary straw chopper, said chaff discharging means being effective forcreating a flow of air for transporting the chaff to the fall-out regionat a pressure that slightly exceeds atmospheric pressure.